The embodiments apply to a feedback control loop, which is intended to control the position of all types of aircraft control surface, such as ailerons, spoilers or an elevator. For example, which forms part of an electrical flight control system of the aircraft, and which comprises said control surface which is mobile, and of which the position in relation to the aircraft is adjusted by at least one actuator, said actuator which adjusts the position of said control surface according to at least one received actuation instruction, at least one sensor which measures the actual position of said control surface, and a (flight control) computer which produces a control surface actuation instruction, transmitted to said actuator, on the basis of said measured actual position and a control instruction calculated on the basis of the action of the pilot on a control stick or the action of the autopilot and the inertial state of the aircraft.
It is known that flight control computers perform, inter alia, the position control of the control surfaces of an aircraft, for example a transport aircraft. The movement of the control surface is generated by an actuator which may be either in active mode or in passive mode. Two actuators are generally provided for each control surface. A computer, referred to as the “master” computer, performs the control by sending a control instruction to the active actuator. The other actuator, associated with a second computer, referred to as the “slave” computer, is forced into passive mode to follow the movement of the control surface. If the master computer detects a fault via specific monitoring means, it switches the active actuator to passive mode, and hands over control to the slave computer which controls the second actuator (then switched to active mode).
The jamming of a control surface, according to the point of flight of the aircraft, may have consequences for the guidance of said aircraft, for the dimensioning of its structure due to the loads generated, and for its performance (non-compliance with ETOPS regulations, for example). It is therefore necessary to be able to detect a fault of this type sufficiently quickly before the consequences in the aircraft are too significant, in particular in order to be able to alert the crew so that it can carry out actions limiting the consequences of this fault. In the context of the description, the term “jamming” of a control surface is understood to mean the situation of a control surface which remains fixed in its current position (when varying control instructions are applied).
In view of the foregoing, at least one object is to overcome the aforementioned disadvantages. In addition, it is at least another object to provide a method, which is particularly robust and which is applicable to any type of aircraft with electrical flight control, for detecting at least a jamming of a control surface of the aircraft, the position of which is controlled by a feedback control loop, the method allowing such a jamming to be detected, regardless of its origin, at levels sufficiently low to avoid adverse consequences in the aircraft, and within a short space of time. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.